[PATCH 19/20] KVM: selftests: Automatically pick min_gpa for allocations based on region type

From: Sean Christopherson <seanjc@google.com>
To: Marc Zyngier <maz@kernel.org>, Oliver Upton <oupton@kernel.org>,
	 Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	 Tianrui Zhao <zhaotianrui@loongson.cn>,
	Bibo Mao <maobibo@loongson.cn>,
	 Huacai Chen <chenhuacai@kernel.org>,
	Anup Patel <anup@brainfault.org>,  Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 Christian Borntraeger <borntraeger@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	 Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Fuad Tabba <fuad.tabba@linux.dev>,
	Joey Gouly <joey.gouly@arm.com>,
	 Steffen Eiden <seiden@linux.ibm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	 Zenghui Yu <yuzenghui@huawei.com>,
	Atish Patra <atish.patra@linux.dev>,
	 Alexandre Ghiti <alex@ghiti.fr>,
	David Hildenbrand <david@kernel.org>,
	linux-arm-kernel@lists.infradead.org,  kvmarm@lists.linux.dev,
	kvm@vger.kernel.org, loongarch@lists.linux.dev,
	 kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
	 linux-kernel@vger.kernel.org,
	Nicholas Piggin <npiggin@gmail.com>,
	 Ritesh Harjani <ritesh.list@gmail.com>
Subject: [PATCH 19/20] KVM: selftests: Automatically pick min_gpa for allocations based on region type
Date: Wed, 26 Aug 2026 16:05:10 -0700	[thread overview]
Message-ID: <20260826230511.972824-20-seanjc@google.com> (raw)
In-Reply-To: <20260826230511.972824-1-seanjc@google.com>

Automatically choose the minimum GPA for physical page allocations based on
the region type instead of sprinkling the logic over various wrappers and
tests.  All usage falls into three categories: (a) don't care, just use the
bare minimum GPA, (b) page tables, use a slightly higher min to keep low
memory available, (c) custom memslot, use the base of the memslot.  I.e.
there isn't a strong need to allow completely custom minimums.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/arm64/vgic_lpi_stress.c     | 11 ++----
 .../testing/selftests/kvm/include/kvm_util.h  | 12 +++---
 tools/testing/selftests/kvm/lib/kvm_util.c    | 38 ++++++++++++++++---
 .../testing/selftests/kvm/lib/x86/processor.c |  3 +-
 .../selftests/kvm/set_memory_region_test.c    |  2 +-
 .../x86/smaller_maxphyaddr_emulation_test.c   |  2 +-
 6 files changed, 44 insertions(+), 24 deletions(-)

diff --git a/tools/testing/selftests/kvm/arm64/vgic_lpi_stress.c b/tools/testing/selftests/kvm/arm64/vgic_lpi_stress.c
index a45c0849a47a..b4c651ea385d 100644
--- a/tools/testing/selftests/kvm/arm64/vgic_lpi_stress.c
+++ b/tools/testing/selftests/kvm/arm64/vgic_lpi_stress.c
@@ -191,28 +191,25 @@ static void setup_test_data(void)
 	gpa_t cmdq_base;
 
 	test_data.device_table = vm_phy_pages_alloc(vm, pages_per_64k,
-						    gpa_base,
 						    MEM_REGION_TEST_EXTRA);
 
 	test_data.collection_table = vm_phy_pages_alloc(vm, pages_per_64k,
-							gpa_base,
 							MEM_REGION_TEST_EXTRA);
 
-	cmdq_base = vm_phy_pages_alloc(vm, pages_per_64k, gpa_base,
-				       MEM_REGION_TEST_EXTRA);
+	cmdq_base = vm_phy_pages_alloc(vm, pages_per_64k, MEM_REGION_TEST_EXTRA);
 	virt_map(vm, cmdq_base, cmdq_base, pages_per_64k);
 	test_data.cmdq_base = cmdq_base;
 	test_data.cmdq_base_va = (void *)cmdq_base;
 
 	test_data.itt_tables = vm_phy_pages_alloc(vm, pages_per_64k * nr_devices,
-						  gpa_base, MEM_REGION_TEST_EXTRA);
+						  MEM_REGION_TEST_EXTRA);
 
 	test_data.lpi_prop_table = vm_phy_pages_alloc(vm, pages_per_64k,
-						      gpa_base, MEM_REGION_TEST_EXTRA);
+						      MEM_REGION_TEST_EXTRA);
 	configure_lpis();
 
 	test_data.lpi_pend_tables = vm_phy_pages_alloc(vm, pages_per_64k * nr_cpus,
-						       gpa_base, MEM_REGION_TEST_EXTRA);
+						       MEM_REGION_TEST_EXTRA);
 
 	sync_global_to_guest(vm, test_data);
 }
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index a0cd1b6598d4..1264cd1a343a 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -1052,11 +1052,10 @@ const char *exit_reason_str(unsigned int exit_reason);
 
 gpa_t ____vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 			     u32 memslot, bool protected, bool naturally_aligned);
-gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
+gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages,
 			   enum kvm_mem_region_type type, bool protected);
 
 static inline gpa_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages,
-				       gpa_t min_gpa,
 				       enum kvm_mem_region_type type)
 {
 	/*
@@ -1064,20 +1063,19 @@ static inline gpa_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages,
 	 * protected memory, as the majority of memory for such VMs is
 	 * protected, i.e. using shared memory is effectively opt-in.
 	 */
-	return __vm_phy_pages_alloc(vm, nr_pages, min_gpa, type,
+	return __vm_phy_pages_alloc(vm, nr_pages, type,
 				    vm_arch_has_protected_memory(vm));
 }
 
-static inline gpa_t vm_phy_page_alloc(struct kvm_vm *vm, gpa_t min_gpa,
+static inline gpa_t vm_phy_page_alloc(struct kvm_vm *vm,
 				      enum kvm_mem_region_type type)
 {
-	return vm_phy_pages_alloc(vm, 1, min_gpa, type);
+	return vm_phy_pages_alloc(vm, 1, type);
 }
 
 static inline gpa_t vm_alloc_page_table_pages(struct kvm_vm *vm, size_t nr_pages)
 {
-	return vm_phy_pages_alloc(vm, nr_pages, KVM_GUEST_PAGE_TABLE_MIN_PADDR,
-				  MEM_REGION_PT);
+	return vm_phy_pages_alloc(vm, nr_pages, MEM_REGION_PT);
 }
 
 static inline gpa_t vm_alloc_page_table(struct kvm_vm *vm)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index e500d1799151..8b5b330a5889 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1473,9 +1473,7 @@ static gva_t ____vm_alloc(struct kvm_vm *vm, size_t sz, gva_t min_gva,
 	u64 pages = (sz >> vm->page_shift) + ((sz % vm->page_size) != 0);
 
 	virt_pgd_alloc(vm);
-	gpa_t gpa = __vm_phy_pages_alloc(vm, pages,
-					   KVM_UTIL_MIN_PFN * vm->page_size,
-					   type, protected);
+	gpa_t gpa = __vm_phy_pages_alloc(vm, pages, type, protected);
 
 	/*
 	 * Find an unused range of virtual page addresses of at least
@@ -2087,11 +2085,39 @@ gpa_t ____vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 	__builtin_unreachable();
 }
 
-gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
+gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages,
 			   enum kvm_mem_region_type type, bool protected)
 {
-	TEST_ASSERT(type < NR_MEM_REGIONS,
-		    "Invalid memory region type '%u'", type);
+	struct userspace_mem_region *region = vm_get_mem_region(vm, type);
+	gpa_t min_gpa;
+
+	TEST_ASSERT(region, "No region for type '%u', memslot '%u'",
+		    type, vm->memslots[type]);
+
+	switch (type) {
+	case MEM_REGION_CODE:
+	case MEM_REGION_DATA:
+	case MEM_REGION_TEST_DATA:
+		/*
+		 * If the region is backed by the default memslot (id=0), use
+		 * selftests' hardcoded minimum PFN, otherwise use the base of
+		 * the custom memory slot that backs the region.
+		 */
+		if (!vm->memslots[type])
+			min_gpa = KVM_UTIL_MIN_PFN * vm->page_size;
+		else
+			min_gpa = region->region.guest_phys_addr;
+		break;
+	case MEM_REGION_PT:
+		min_gpa = KVM_GUEST_PAGE_TABLE_MIN_PADDR;
+		break;
+	case MEM_REGION_TEST_EXTRA:
+		min_gpa = region->region.guest_phys_addr;
+		break;
+	default:
+		TEST_FAIL("Invalid memory region type '%u'", type);
+		break;
+	}
 
 	return ____vm_phy_pages_alloc(vm, nr_pages, min_gpa, vm->memslots[type],
 				      protected, false);
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index 39d9ca6ceb1d..479e9a481687 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -1474,8 +1474,7 @@ void setup_smram(struct kvm_vm *vm, struct kvm_vcpu *vcpu, gpa_t smram_gpa,
 	vm_override_mem_region(vm, MEM_REGION_TEST_EXTRA, VM_MEM_SRC_ANONYMOUS,
 			       smram_gpa, SMRAM_MEMSLOT, SMRAM_PAGES);
 
-	TEST_ASSERT(vm_phy_pages_alloc(vm, SMRAM_PAGES, smram_gpa,
-				       MEM_REGION_TEST_EXTRA) == smram_gpa,
+	TEST_ASSERT(vm_phy_pages_alloc(vm, SMRAM_PAGES, MEM_REGION_TEST_EXTRA) == smram_gpa,
 		    "Could not allocate guest physical addresses for SMRAM");
 
 	memset(addr_gpa2hva(vm, smram_gpa), 0x0, SMRAM_SIZE);
diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index 160bbe3d7203..bfa5ac8ce029 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -124,7 +124,7 @@ static struct kvm_vm *spawn_vm(struct kvm_vcpu **vcpu, pthread_t *vcpu_thread,
 	 * Allocate and map two pages so that the GPA accessed by guest_code()
 	 * stays valid across the memslot move.
 	 */
-	gpa = vm_phy_pages_alloc(vm, 2, MEM_REGION_GPA, MEM_REGION_TEST_EXTRA);
+	gpa = vm_phy_pages_alloc(vm, 2, MEM_REGION_TEST_EXTRA);
 	TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc\n");
 
 	virt_map(vm, MEM_REGION_GPA, MEM_REGION_GPA, 2);
diff --git a/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c b/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c
index 4e125eb5e0cf..8d1822717abd 100644
--- a/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c
+++ b/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c
@@ -67,7 +67,7 @@ int main(int argc, char *argv[])
 			       MEM_REGION_SIZE / PAGE_SIZE);
 
 	gpa = vm_phy_pages_alloc(vm, MEM_REGION_SIZE / PAGE_SIZE,
-				 MEM_REGION_GPA, MEM_REGION_TEST_EXTRA);
+				 MEM_REGION_TEST_EXTRA);
 	TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc");
 	virt_map(vm, MEM_REGION_GVA, MEM_REGION_GPA, 1);
 	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
-- 
2.55.0.887.g758fc8c411-goog

